This invention relates to an improved closure for covering and sealing an aperture in a panel.
As a general practice, various panels as well as the floor pan of an automobile body are formed with relatively large apertures which permit liquid coating such as paint, primer and rust inhibitor to drain from the panels after the panels have been dipped in the liquid. Then these holes are covered and sealed to prevent dirt, moisture, exhaust fumes and the like from entering the vehicle when in use.
Conventionally, these closures take the form of a flat metal plate or cover which is secured to the panel by means of screws or by resilient fingers which project through and resiliently engage the aperture wall. The closure usually also includes a gasket ring extending around the plate rim to provide a fluid-tight seal between the plate and the panel. In some cases, the ring is made of a material which melts to some degree and flows when the panel is heated to a relatively high temperature as when the panel is baked after it is primed or painted. The ring material melts sufficiently to flow between and adhere to those surfaces to provide a seal and inhibit relative movement between the two. Examples of such closures are described in U.S. Pat. No. 3,944,107 and British Pat. No. 1,390,125.
The securement of the closures to the panels by means of screws takes a relatively long time and therefore it is a relatively costly step in the vehicle assembly process considering the number of such drain openings that have to be closed in each vehicle. On the other hand, closures having sprung fingers, clips, or other such resilient retaining projections have not proven to be entirely satisfactory either. This is because such resilient projections tend to be too flexible in the inward direction so that they bend away from the aperture wall when the vehicle panel is jounced and bounced in normal use. Resultantly, the closure is partially or completely knocked out of the aperture permitting ingress of dirt, moisture and fumes. Furthermore, the sealing ring cannot be relied on to prevent dislodgement of these closures because the adhesion between the ring material and the closure and panel surfaces is not strong enough to withstand the vibrations sustained by the panel when, as is usually the case, those surfaces are oily and dirty.
Also in some applications, it is desirable for the closure plate and resilient retaining legs to be stamped and formed from a single piece of material for cost reasons. A cold rolled steel is an acceptable material for the closure plate because it is relatively strong and rigid. However as that material is not known for its resilience, it is not a particularly desirable material for the closure retaining fingers. Therefore such one-piece closures are particularly susceptible to being knocked out of the panels in which they are installed.